title: Sporadic colorectal cancer development shows rejuvenescence regarding epithelial proliferation and apoptosis.
abstract: OBJECTIVE
  Sporadic colorectal cancer (CRC) development is a sequential process showing age-dependency, uncontrolled epithelial proliferation and decreased apoptosis. During juvenile growth cellular proliferation and apoptosis are well balanced, which may be perturbed upon aging. Our aim was to correlate proliferative and apoptotic activities in aging human colonic epithelium and colorectal cancer. We also tested the underlying molecular biology concerning the proliferation- and apoptosis-regulating gene expression alterations.
  
  
  METHODS
  Colorectal biopsies from healthy children (n1 = 14), healthy adults (n2 = 10), adult adenomas (n3 = 10) and CRCs (n4 = 10) in adults were tested for Ki-67 immunohistochemistry and TUNEL apoptosis assay. Mitosis- and apoptosis-related gene expression was also studied in healthy children (n1 = 6), adult (n2 = 41) samples and in CRC (n3 = 34) in HGU133plus2.0 microarray platform. Measured alterations were confirmed with RT-PCR both on dependent and independent sample sets (n1 = 6, n2 = 6, n3 = 6).
  
  
  RESULTS
  Mitotic index (MI) was significantly higher (p<0.05) in intact juvenile (MI = 0.33±0.06) and CRC samples (MI = 0.42±0.10) compared to healthy adult samples (MI = 0.15±0.06). In contrast, apoptotic index (AI) was decreased in children (0.13±0.06) and significantly lower in cancer (0.06±0.03) compared to healthy adult samples (0.17±0.05). Eight proliferation- (e.g. MKI67, CCNE1) and 11 apoptosis-associated genes (e.g. TNFSF10, IFI6) had altered mRNA expression both in the course of normal aging and carcinogenesis, mainly inducing proliferation and reducing apoptosis compared to healthy adults. Eight proliferation-associated genes including CCND1, CDK1, CDK6 and 26 apoptosis-regulating genes (e.g. SOCS3) were differently expressed between juvenile and cancer groups mostly supporting the pronounced cell growth in CRC.
  
  
  CONCLUSIONS
  Colorectal samples from children and CRC patients can be characterized by similarly increased proliferative and decreased apoptotic activities compared to healthy colonic samples from adults. Therefore, cell kinetic alterations during colorectal cancer development show uncontrolled rejuvenescence as opposed to the controlled cell growth in juvenile colonic epithelium.
authors.affiliation: 2nd Department of Internal Medicine, Semmelweis University, Budapest, Hungary.
authors.forename: Katalin
authors.initials: K
authors.lastname: Leiszter
authors.forename: Orsolya
authors.initials: O
authors.lastname: Galamb
authors.forename: Ferenc
authors.initials: F
authors.lastname: Sipos
authors.forename: Tibor
authors.initials: T
authors.lastname: Krenács
authors.forename: Gábor
authors.initials: G
authors.lastname: Veres
authors.forename: Barnabás
authors.initials: B
authors.lastname: Wichmann
authors.forename: Alexandra
authors.initials: A
authors.lastname: Kalmár
authors.forename: Árpád V
authors.initials: ÁV
authors.lastname: Patai
authors.forename: Kinga
authors.initials: K
authors.lastname: Tóth
authors.forename: Gábor
authors.initials: G
authors.lastname: Valcz
authors.forename: Béla
authors.initials: B
authors.lastname: Molnár
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Tulassay
mesh_terms: D000328:Adult; D000375:Aging / Q000473:pathology; D017209:Apoptosis; D063646:Carcinogenesis; D049109:Cell Proliferation; D002648:Child; D015179:Colorectal Neoplasms / Q000235:genetics / Q000473:pathology* / Q000503:physiopathology*; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D007413:Intestinal Mucosa / Q000473:pathology*; D008297:Male